PPC/s390: [regexp] Add an offset argument CheckAtStart

Port 2e0bc516

Original Commit Message:

    Similar to CheckNotAtStart, one can now apply an offset to the
    CheckAtStart operation. Due to a recent change, all callsites of
    CheckNotAtStart now need to pass an offset, whereas previously the
    offset was just assumed to be zero.

R=jgruber@chromium.org, joransiu@ca.ibm.com, jyan@ca.ibm.com, michael_dawson@ca.ibm.com
BUG=
LOG=N

Change-Id: I255ed27bd0d5bccfb9851696ca25f2bb4a984981
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/1775721Reviewed-by: Jakob Gruber <jgruber@chromium.org>
Reviewed-by: Joran Siu <joransiu@ca.ibm.com>
Commit-Queue: Milad Farazmand <miladfar@ca.ibm.com>
Cr-Commit-Position: refs/heads/master@{#63452}

src/regexp/ppc/regexp-macro-assembler-ppc.cc

@@ -189,15 +189,14 @@ void RegExpMacroAssemblerPPC::CheckCharacterGT(uc16 limit, Label* on_greater) {
   BranchOrBacktrack(gt, on_greater);
 }
 
-
-void RegExpMacroAssemblerPPC::CheckAtStart(Label* on_at_start) {
+void RegExpMacroAssemblerPPC::CheckAtStart(int cp_offset, Label* on_at_start) {
   __ LoadP(r4, MemOperand(frame_pointer(), kStringStartMinusOne));
-  __ addi(r3, current_input_offset(), Operand(-char_size()));
+  __ addi(r3, current_input_offset(),
+          Operand(-char_size() + cp_offset * char_size()));
   __ cmp(r3, r4);
   BranchOrBacktrack(eq, on_at_start);
 }
 
-
 void RegExpMacroAssemblerPPC::CheckNotAtStart(int cp_offset,
                                               Label* on_not_at_start) {
   __ LoadP(r4, MemOperand(frame_pointer(), kStringStartMinusOne));

src/regexp/ppc/regexp-macro-assembler-ppc.h

@@ -23,7 +23,7 @@ class V8_EXPORT_PRIVATE RegExpMacroAssemblerPPC
   virtual void AdvanceRegister(int reg, int by);
   virtual void Backtrack();
   virtual void Bind(Label* label);
-  virtual void CheckAtStart(Label* on_at_start);
+  virtual void CheckAtStart(int cp_offset, Label* on_at_start);
   virtual void CheckCharacter(unsigned c, Label* on_equal);
   virtual void CheckCharacterAfterAnd(unsigned c, unsigned mask,
                                       Label* on_equal);

src/regexp/s390/regexp-macro-assembler-s390.cc

@@ -178,9 +178,10 @@ void RegExpMacroAssemblerS390::CheckCharacterGT(uc16 limit, Label* on_greater) {
   BranchOrBacktrack(gt, on_greater);
 }
 
-void RegExpMacroAssemblerS390::CheckAtStart(Label* on_at_start) {
+void RegExpMacroAssemblerS390::CheckAtStart(int cp_offset, Label* on_at_start) {
   __ LoadP(r3, MemOperand(frame_pointer(), kStringStartMinusOne));
-  __ AddP(r2, current_input_offset(), Operand(-char_size()));
+  __ AddP(r2, current_input_offset(),
+          Operand(-char_size() + cp_offset * char_size()));
   __ CmpP(r2, r3);
   BranchOrBacktrack(eq, on_at_start);
 }

src/regexp/s390/regexp-macro-assembler-s390.h

@@ -23,7 +23,7 @@ class V8_EXPORT_PRIVATE RegExpMacroAssemblerS390
   virtual void AdvanceRegister(int reg, int by);
   virtual void Backtrack();
   virtual void Bind(Label* label);
-  virtual void CheckAtStart(Label* on_at_start);
+  virtual void CheckAtStart(int cp_offset, Label* on_at_start);
   virtual void CheckCharacter(unsigned c, Label* on_equal);
   virtual void CheckCharacterAfterAnd(unsigned c, unsigned mask,
                                       Label* on_equal);